sqlj.runtime
Interface PositionedIterator

All Superinterfaces:

ResultSetIterator

public interface PositionedIterator

extends ResultSetIterator

An interface implemented by all iterators that employ a by-position binding strategy. All such iterators depend on the position of the columns of the data to which they are bound, as opposed to the names of the columns to which they are bound.

In addition to implementing this interface, position-bound iterator implementations will provide:

• A public constructor which takes an RTResultSet as a parameter. If the construction of a positioned iterator results in an exception being thrown, it is assumed that the iterator automatically closes the underlying result set. This only applies to exceptions thrown during construction. This constructor is for internal use of the SQLJ runtime only. Please use the SQLJ CAST statement instead.
• An accessor method for each column in the expected result. The name of the accessor method for the n^th column will be getColN(). These accessor methods are for internal use by the SQLJ runtime only. Please use the SQLJ FETCH ... INTO statement to access the colums of a positional iterator.

A common usage of a PositionedIterator is as follows:

#sql iterator StringIter(String);

[...]

IntIter posIter;
String val;

#sql [ctx] posIter = { SELECT the_value FROM tab WHERE the_key = 1 };

try {
    while (true) {
        #sql { FETCH :posIter INTO :val };
        if (c.endFetch()) break;
        [...]
    } 
} finally {
    posIter.close();
}

See Also:

NamedIterator, ResultSetIterator

Fields inherited from interface sqlj.runtime.ResultSetIterator

ASENSITIVE, FETCH_FORWARD, FETCH_REVERSE, FETCH_UNKNOWN, INSENSITIVE, SENSITIVE

Method Summary

boolean

endFetch() Returns true iff the iterator is not positioned on a row.

Methods inherited from interface sqlj.runtime.ResultSetIterator

clearWarnings, close, getFetchSize, getResultSet, getRow, getSensitivity, getWarnings, isClosed, next, setFetchSize

Method Detail

endFetch

public boolean endFetch()
                 throws java.sql.SQLException

Returns true iff the iterator is not positioned on a row. This method is used to determine the success of a FETCH ... INTO statement; it returns true if the last attempt to fetch a row failed, false if the last attempt was successful. Rows are attempted to be fetched when the next() method is called (which is called implicitely during the execution of a FETCH ... INTO statement). Note: If next() has not yet been called, this method returns true;

A common usage of this method is as follows:

while (true) {
    #sql { FETCH :c INTO ... };
    if (c.endFetch()) break;
    [...]
}

Throws:

java.sql.SQLException - if a databse access error occurs

See Also:

ResultSetIterator.next()